
/*-
 * Copyright (c) 1985, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that: (1) source distributions retain this entire copyright notice and
 * comment, and (2) distributions including binaries display the following
 * acknowledgement:  ``This product includes software developed by the
 * University of California, Berkeley and its contributors'' in the
 * documentation or other materials provided with the distribution and in
 * all advertising materials mentioning features or use of this software.
 * Neither the name of the University nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include "config.h"		  /* To get #define SOL20       Vesa */
#include "sys.h"
#include "common.h"
#include "nameser.h"
#include "resolv.h"

/*
 * Resolver state default settings
 */

struct state _res = {
    RES_TIMEOUT,   /* retransmition time interval */
    4,		   /* number of times to retransmit */
    RES_DEFAULT,   /* options flags */
    1,		   /* number of name servers */
};

/*
 * Set up default settings.  If the configuration file exist, the values
 * there will have precedence.  Otherwise, the server address is set to
 * INADDR_ANY and the default domain name comes from the gethostname().
 *
 * The configuration file should only be used if you want to redefine your
 * domain or run without a server on your machine.
 *
 * Return 0 if completes successfully, -1 on error
 */
int res_init ()
{
    register FILE *fp;
    register char *cp, *dp, **pp;
    extern u_long inet_addr ();
    register int n;
    char buf[BUFSIZ];
    extern char *getenv ();
    int nserv = 0; /* number of nameserver records read from file */
    int norder = 0;
    int haveenv = 0;
    int havesearch = 0;

    _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
    _res.nsaddr.sin_family = AF_INET;
    _res.nsaddr.sin_port = htons (NAMESERVER_PORT);
    _res.nscount = 1;

    /* Allow user to override the local domain definition */
    if ((cp = getenv ("LOCALDOMAIN")) != NULL) {
	(void) strncpy (_res.defdname, cp, sizeof (_res.defdname));
	haveenv++;
    }
    if ((fp = fopen (_PATH_RESCONF, "r")) != NULL) {
	/* read the config file */
	while (fgets (buf, sizeof (buf), fp) != NULL) {
	    /* read default domain name */
	    if (!strncmp (buf, "domain", sizeof ("domain") - 1)) {
		if (haveenv)	  /* skip if have from environ */
		    continue;
		cp = buf + sizeof ("domain") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		(void) strncpy (_res.defdname, cp,
				sizeof (_res.defdname) - 1);
		if ((cp = index (_res.defdname, '\n')) != NULL)
		    *cp = '\0';
		havesearch = 0;
		continue;
	    }
	    /* set search list */
	    if (!strncmp (buf, "search", sizeof ("search") - 1)) {
		if (haveenv)	  /* skip if have from environ */
		    continue;
		cp = buf + sizeof ("search") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		(void) strncpy (_res.defdname, cp,
				sizeof (_res.defdname) - 1);
		if ((cp = index (_res.defdname, '\n')) != NULL)
		    *cp = '\0';
		/*
		 * Set search list to be blank-separated strings
		 * on rest of line.
		 */
		cp = _res.defdname;
		pp = _res.dnsrch;
		*pp++ = cp;
		for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
		    if (*cp == ' ' || *cp == '\t') {
			*cp = 0;
			n = 1;
		    }
		    else if (n) {
			*pp++ = cp;
			n = 0;
		    }
		}
		/* null terminate last domain if there are excess */
		while (*cp != '\0' && *cp != ' ' && *cp != '\t')
		    cp++;
		*cp = '\0';
		*pp++ = 0;
		havesearch = 1;
		continue;
	    }
	    /* read nameservers to query */
	    if (!strncmp (buf, "nameserver", sizeof ("nameserver") - 1) &&
		nserv < MAXNS) {
		cp = buf + sizeof ("nameserver") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		if ((_res.nsaddr_list[nserv].sin_addr.s_addr =
		     inet_addr (cp)) == (unsigned) -1) {
		    _res.nsaddr_list[nserv].sin_addr.s_addr = INADDR_ANY;
		    continue;
		}
		_res.nsaddr_list[nserv].sin_family = AF_INET;
		_res.nsaddr_list[nserv].sin_port = htons (NAMESERVER_PORT);
		nserv++;
		continue;
	    }
	    /* read service order */
	    if (!strncmp (buf, "order", sizeof ("order") - 1)) {
		cp = buf + sizeof ("order") - 1;
		while (*cp == ' ' || *cp == '\t')
		    cp++;
		if ((*cp == '\0') || (*cp == '\n'))
		    continue;
		norder = 0;
		do {
		    if ((dp = index (cp, ',')) != NULL)
			*dp = '\0';
		    if (norder >= MAXSERVICES)
			continue;
		    if (!strncmp (cp, "bind", sizeof ("bind") - 1))
			_res.order[norder++] = RES_SERVICE_BIND;
		    else if (!strncmp (cp, "local", sizeof ("local") - 1))
			_res.order[norder++] = RES_SERVICE_LOCAL;
		    cp = dp + 1;
		}
		while (dp != NULL);
		_res.order[norder] = RES_SERVICE_NONE;
		continue;
	    }
	}
	if (nserv > 1)
	    _res.nscount = nserv;
	(void) fclose (fp);
    }
    if (_res.defdname[0] == 0) {
	if (gethostname (buf, sizeof (_res.defdname)) == 0 &&
	    (cp = index (buf, '.')))
	    (void) strcpy (_res.defdname, cp + 1);
    }
    /* find components of local domain that might be searched */
    if (havesearch == 0) {
	pp = _res.dnsrch;
	*pp++ = _res.defdname;
	for (cp = _res.defdname, n = 0; *cp; cp++)
	    if (*cp == '.')
		n++;
	cp = _res.defdname;
	for (; n >= LOCALDOMAINPARTS && pp < _res.dnsrch + MAXDFLSRCH; n--) {
	    cp = index (cp, '.');
	    *pp++ = ++cp;
	}
	*pp++ = 0;
    }
    /* default search order to bind only */
    if (norder == 0) {
	_res.order[0] = RES_SERVICE_BIND;
	_res.order[1] = RES_SERVICE_NONE;
    }
    _res.options |= RES_INIT;
    return (0);
}
